The innovations and related subject matter disclosed herein (collectively referred to as the “disclosure”) generally pertain to electrosurgical systems, such as electrosurgical devices and related electrical circuitry and methods. More particularly, but not exclusively, the innovations relate to electrosurgical systems having a movable electrode configured to accommodate a variation in spacing between a handpiece held by an operator (e.g., in an operator's hand) and an intended treatment site (e.g., in contact with a portion of the movable electrode). For example, an electrosurgical handpiece can have a housing configured to be grasped by a user and an energizable electrode configured to move relative to the housing. With such a handpiece, the electrode can continuously provide a therapeutic energy to a treatment site notwithstanding that an operator's hand (and the handpiece) might move relatively closer to and relatively farther from the treatment site during the course of therapy. In some particular embodiments of disclosed electrosurgical systems, a movable electrode can also be configured to reduce or eliminate arcing between an energizable surface of the electrode and a patient's skin.
U.S. patent application Ser. No. 13/175,618, published as U.S. Publication No. 2013/0006239, (referred to as “the '618 Application” and the contents of which are incorporated herein in their entirety, for all purposes) is commonly owned with this application and discloses, inter alia, an electrosurgical system of the type shown in FIG. 1, herein. FIG. 1 shows an electrosurgical system having a control unit 34 and an electrosurgical device 10. The electrosurgical device 10 includes a housing 12, e.g., for containing circuitry, and an energizable electrode 18 configured to treat a target site on or in a patient's body. The housing 12 can be configured as a handpiece, as shown for example in FIG. 1. In other instances, a graspable handpiece is spaced from the housing.
The control unit 34 is configured to provide power to the electrosurgical device 10 for energizing the electrode. As described more fully in the '618 Application, the control unit 34 can be configured to provide energy having a selected combination of waveform and frequency. Some control units 34 are configured to provide RF energy to the electrosurgical device 10.
As FIG. 1 shows, a cable 32 can extend between an electrical connector 33 on the control unit 34 and an electrical connector 31 on the electrosurgical device so as to electrically couple one or more conductive elements on or within the device 10 to one or more corresponding conductive elements of the controller 34. Some known control units provide three output terminals, with one of the terminals being an energizable terminal for conveying therapeutic energy, e.g., RF energy, to an energizable element of a handpiece. Such a control unit 34 is usually configured to energize the energizable terminal when a circuit between the two remaining output terminals is completed, as through the closing of a user actuatable switch 14.
Some known electrosurgical control units, such as control units manufactured by Ellman International, Inc. under the brand SURIGTRON and described in U.S. Pat. No. 6,652,514, the contents of which are incorporated herein by reference in their entirety, provide a three-wire output connector for powering and controlling electrosurgical handpieces. Conventional control units can generate, for example, one or more radio-frequency (RF) modulated waveforms, e.g., at a frequency of about 4 mega-Hertz (MHz), which can be delivered to a target site by way of an electrosurgical handpiece having an energizable electrode defining an active surface.
In some cases, the active surface of an electrosurgical system can be configured for non-ablative electrosurgery. As used herein, an ablative procedure is one where the electrode and power settings result in cutting, coagulation, vaporization or other such traumatic disruption to the integrity of treated tissue, and a non-ablative procedure is one where such cutting, coagulation, vaporization or other such traumatic disruption to the integrity of treated tissue does not result.
U.S. patent application Ser. No. 12/455,661, published as U.S. Pub. No. 2010/0312233, which is also owned by the Assignee of this application, and which is hereby incorporated by reference in its entirety, describes, inter alia, shock-free electrosurgical handpieces. Some handpieces described in the '233 Publication have an internal switch that prevents an active electrode surface from being energized unless the surface is in actual contact with a patient's skin. A de-energized electrode surface reduces or eliminates the likelihood that a patient might receive an electrical shock from an electrical arc spanning an air gap between the electrode surface and the patient's skin as the electrode is applied to or removed from the patient's skin. In some handpieces described in the '233 Publication, arcing can occur inside the handpiece between a portion of the electrode and an energizable element within the handpiece if the electrode becomes spaced from the energizable element, as when a user lifts the handpiece away from a treatment site and before the electrode lifts away from the treatment site.
However, in some instances, a user can inadvertently lift the handpiece away from the treatment site while maintaining physical contact between the electrode and the treatment site. Such inadvertent lifting of the handpiece away from the treatment site can inadvertently cause the electrode to separate from the energizable element, allowing arcing between the electrode and the energizable element to occur. Over many cycles, such arcing can degrade one or more electrically conductive surfaces of the internal switch. Inadvertent opening and closing of the internal switch can prematurely degrade one or more such electrically conductive surfaces of the internal switch.
Accordingly, there remains a need for improved electrosurgical systems, including improved electrosurgical handpieces, configured to accommodate position-dependent variations in the force applied toward (or away from) a treatment site by a user. There also remains a need for such improved electrosurgical systems configured to prevent, or at least inhibit or otherwise reduce the occurrence of, inadvertent arcing within the handpiece. As well, a need remains for an improved electrosurgical handpiece configured to prevent or at least inhibit premature degradation of an internal switch or other portion of an electrical circuit associated with the handpiece.